What does this compressor part do?

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  1. Hi Willyr,

    I have a small single pump compressor running on 240 volts that has not had a lot of use but will just not build pressure above 10 psi in the tank. It was bought in the UK through a retailer called Machine Mart and carries the brand name of Clarke.

    After reading through your excellent information I suspect that the problem lies with the compressor tank check valve with perhaps a bit of debris not allowing the valve to seat properly. The inlet side of the pump sucks very well and the outlet appears to pump well too.

    However, before reading your excellent articles I started by looking over a few things and one components purpose has me baffled. On the airline from the pump enroute to the air receiver/tank (but within 3″ of the pump itself) is a spring loaded brass valve where the airline takes a right angled turn downwards towards the receiver and pressure switch. What is the purpose of this valve please? Is it to purge compressed air from the pipe to enable a restart after the tanks pressure drops like an unloader valve? I thought that that valve was always in the pressure switch ( which is about a foot below) so I’m unsure what this extra valve is called to enable me to buy a replacement, since i have damaged it.

    Any advice gratefully received!


    • Please add a new comment and use the just-installed image upload function to include a few pictures of your air compressor and the component in question. We will take a look and see if we can identify the part for you. It’s always good to include a model number of any air compressor you are interested in working on, as sometimes the model number will lead to an on-line image.

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